The Impact of the Neutrophil-to-Lymphocyte Ratio on In-Hospital Outcomes in Patients With Acute ST-Segment Elevation Myocardial Infarction.

Introduction The neutrophil-to-lymphocyte ratio (NLR) is a significant predictor of cardiovascular diseases, influencing their progression and prognosis. The exact role of the NLR in acute ST-segment elevation myocardial infarction (STEMI) is unclear. We investigated the possible association between peak NLR values within the first three days after STEMI onset and in-hospital outcomes in patients undergoing primary percutaneous coronary intervention (PCI). Methods This retrospective study included 641 patients who were diagnosed with acute STEMI and treated with primary PCI for 18 months at Dr. Siyami Ersek Hospital. The NLR was calculated using the maximum values obtained during the first three days after admission. The patients were divided into quartiles according to their NLR values for further analysis of potential complications during and after hospitalization, up to a follow-up period of three months. Results Significant differences were found in factors such as age, body mass index (BMI), and length of hospital stay among these groups. Specifically, we found that in-hospital mortality rates were significantly higher in the Q4 group, and there were variations in target vessel revascularization (TVR) rates, major adverse cardiac events (MACE) rates, and other clinical outcomes. Some parameters, such as reinfarction rates and certain procedural outcomes, did not show significant differences among the groups. However, despite the differences, most of the patients achieved successful outcomes after PCI, with the best results in the low NLR group and the worst results in the high NLR group. Conclusion Higher NLR values were associated with a higher risk of unfavorable outcomes during hospitalization.